The present invention relates to methods of treating subterranean formations with treatment fluids comprising nanoparticle suspension aids.
Gelled fluids, because of the increased viscosity, are useful in a variety of subterranean operations including those that control fluid flow (e.g., enhanced oil recovery, fluid loss control, and fluid diversion) or transport of particles like proppants and gravel. Additionally, crosslinking agents are often used to increase the viscosity and stability of the gelled fluid to further increase the fluid's utility in some downhole environments.
With respect to controlling fluid flow, gelled fluids generally enable more control over the movement of the gelled fluid or another fluid that contacts the gelled fluid. For example, a gelled fluid may be utilized for enhanced oil recovery by pushing hydrocarbons through a formation from an injection well to a production well. Additionally, in fluid diversion, a gelled fluid can prevent another fluid from entering a zone by effectively sealing off the zone. In fluid loss control, the increased viscosity of gelled fluids mitigates the loss of the gelled fluid into the subterranean formation. Accordingly, higher viscosity gels, i.e., higher concentrations of gelling agents and crosslinkers, can provide better fluid flow control in a variety of applications.
With respect to transporting and placing particles, gelled fluids aid in the suspension of the particles so that the particles may be transported to and placed in a desired location within a subterranean formation, e.g., in a proppant pack and/or a gravel pack. It is generally preferred to perform particle placement operations with the highest possible particle concentration. Increasing the particle concentration in a treatment fluid generally requires a higher concentration of gelling agents and/or crosslinker.
However, in each of these gelled fluid applications, use of higher gelling agent and/or crosslinker concentrations can lead to reduced pumpability of the treatment fluid, damage of the wellbore or subterranean formation, and/or a need for remedial operations to clean out any gelled fluids from the wellbore, subterranean formation, or particle pack. Further, gelling agents designed to be operable at higher temperatures, e.g., approaching the limits of chemical decomposition at about 300° F., can be more problematic in each of these areas as a result of, inter alia, higher molecular weights, higher degrees of crosslinking, and more chemically stable structures. Accordingly, subterranean operations are often performed at moderate gelling agent and/or crosslinking agent concentrations to mitigate any complications. As many gelling agents are used in a variety of fluids outside the oil and gas industry, the demand is increasing while supply is decreasing. Therefore, the cost of gelling agents are increasing, and consequently the cost of subterranean operations, especially considering the amount of the gelling agent needed for a single treatment.
Therefore, a practical replacement and/or supplement to gelling agents and/or crosslinking agents that can overcome any shortcomings and yet still effectively carry particulate may be of value to one of ordinary skill in the art.